Industrial Noise & Vibration Centre

+44 1753 698 800

Noise Control Case Studies

An elegant engineering solution to your noise or vibration problem may already be available. Search the largest database of noise control at source case studies in the world for best practice alternatives to conventional, high-cost palliatives such as acoustic enclosures, silencers, barriers etc.

Showing 31 to 45 out of 104
  • nuisance
  • noise control
  • environmental noise

Corrugator source noise control eliminates noise nuisance and PPE – and reduces costs by 80%…

corrugator noise reduction.jpg

The highly tonal noise from corrugators and slitters at Northern Packaging, the premiere packaging company in the north of England, had caused complaints from local residents and was subject to an abatement notice. The company was quoted £150,000 for conventional environmental noise control (building modifications) but with no guarantee it would solve the problem. An EHO who had been on one of our BAT courses suggested we might have an alternative approach.Following a best practice audit, we developed noise control at source engineering modifications to cut the noise generated by the corrugator and slitter machines inside the building. Installed by Sound Damped Steel, these not only reduced the problem tonal noise by up to 9dB, but also eliminated the requirement for mandatory PPE – a double benefit. In addition, the cost was only c£25,000, an 80% saving over the proposed conventional noise control methods.

This is a typical example of the success of our approach to environmental noise problems, re-defining noise control best practice by developing elegant engineering solutions in place of the high cost, conventional palliatives usually considered. Moreover, to the delight of the company, the project also satisfied their mandatory noise control requirements under the Control of Noise at Work Regulations – at no added cost. This approach should be standard practice for environmental noise pollution problems. Controlling noise at source is always the first step in the process of defining BAT or BPM.

  • nuisance
  • fan noise attenuation
  • noise control
  • environmental noise

Lifting a Fan Noise Abatement Notice

lifting fan noise abatement notice

Approaching £50000 had been spent on silencing two large, roof mounted fans in an attempt to satisfy local complainants and the Environment Agency authorities – unfortunately without any success due to a lack of diagnosis of the cause of the noise problem. When the company approached us to provide them with a solution, we asked them to email us a couple of video clips of the fans.

Our initial diagnostic analysis of the video sound-tracks showed that the noise issue was caused by the interaction between the blade pass tones of the 2 similar fans that caused "beating" - modulation of the tonal level that adds to the subjective nuisance. This allowed us to design our unique Quiet Fan technology aerodynamic inserts to reduce the noise by over 20dB at source without enclosures, silencers or lagging – permanently and without maintenance. This was achieved with minimal down-time and at a tiny fraction of the cost of conventional alternatives. Read more on fan noise control without attenuators.

  • nuisance
  • noise control
  • fans
  • environmental noise
  • extract system

Fume Extract Fan Noise Control

dust extract system low frequency noise attenuation

There are elegant, low-cost solutions to reduce fume or dust extract fan noise that is a common cause of complaints. They can also be used to reduce occupational noise hazards from these sources. Conventional extract fan silencing is not only subject to clogging, but can also increase backpressure, reducing system efficiency - not what you need from these extract systems.

A large weld booth fume extractor fan system generated high-level low-frequency tones at 35Hz and harmonics that caused extensive complaints in nearby offices. Diagnostic measurements proved that the major problem was an in-duct standing wave resonance in the manifold that was amplified by panel resonances in the filter enclosure. The elegant solution was to insert an air-guide plate into the ductwork to reduce turbulence, fitting an acoustic absorbent plug into an end cap to create an anechoic termination and applying stiffening ribs to detune the noise radiating panels.

These measures were fitted within a day at very low cost, not only eliminating the low-frequency tones (30dB reduction), but also dramatically improving the fume extract fan efficiency and hence reducing running costs.

View the detailed guide to fume and scrubber extractor fan noise reduction and silencing techniques.

  • chiller fan
  • environmental noise
  • fan noise attenuation

Data Centre Server Chiller Farm – efficient noise control

data center server farm fan noise attenuation

Data centres (or "data centers" in the US) require a lot of cooling - which involves noisy chiller fans, air handling units (AHUs), cooling towers and condensers. Moreover, in addition to the general fan air noise, there are often low-frequency tonal elements (hums or drones) that cannot be silenced using conventional attenuators and acoustic enclosures and barriers. Unfortunately, poor diagnosis of the exact causes of noise complaints has often led to ineffective control of the noise from data centers that not only fail to solve the problem, but also compromise cooling efficiency.

Fortunately, there are effective low-cost alternatives that can actually increase cooling capacity...

Data centre noise problems - low-cost precision attenuation

A Noise Abatement Notice had been issued re the AHU noise from a large array of chillers at this data centre. The company had already spent nearly £100k on noise control with very little success and was considering claiming Best Practicable means (BPM) in court when the council suggested they might like to get a second opinion from us to avoid the legal route…

We carried out a very accurate diagnosis of the precise noise elements that were the cause of the complaints. Based on this evaluation, we designed a set of precise retrofit noise reduction measures that were guaranteed to be BPM. The innovative noise control measures included:

  • Air handling units: changing the geometry of the AHUs and introducing internal modifications to convert existing elements into effective acoustic attenuators cut the broadband noise by >10dB(A) with no effect on fan efficiency
  • Chiller condenser fans: the noise from these units was reduced by fitting a combination of high-efficiency damping coupled with internal and fan modifications, reducing the overall noise by around 8dB(A) with no effect on performance. Improvements were also made to the existing noise barriers.
data centre noise attenuation signatures.jpg

These noise mitigation measures cut the overall noise at the complainants from 48.5dB(A) down to 36.5dB(A) (as illustrated by the audio recording above and by this noise signature) without affecting the performance of the cooling systems. In addition to the reduced broadband noise, the tonal "character" of the noise was also eliminated.

The whole process took approximately 6 weeks from start to finish and completely resolved the complaint issue.

Cost savings on noise control

The overall effect was to reduce the data centre cooling system noise by 15dB at less than half the previously expected cost. If this approach had been implemented in the first place, the company would have saved over £100k, the council would have saved resources and the complainants would not have had to suffer unnecessary disturbance over a 2 year period.

More details on how to reduce environmental noise from data centers

More on chiller, condenser and heat exchanger AHU fan noise reduction.

  • nuisance
  • planning
  • noise control
  • environmental noise

Brown Field Site Development – noise control makes 200 houses possible

Noise reduction allows site planning permission

High levels of environmental noise from nearby industrial premises affecting over 18 acres of mixed brown-field and farmland had caused the planners to assess the site as unsuitable for housing. However, as the City Council was aware of our expertise in industrial and fan noise control and they suggested that the Planning Consultants contact us for a second opinion to see if there was a solution.

The developers then paid for us to both evaluate the noise control options and to design permanent solutions (including our Quiet Fan noise control technology for the problem fans) that could be implemented at each of the 4 companies involved. The companies themselves were extremely happy with the process as they had all had previous noise complaints that were now resolved. Moreover, the noise mitigation measures permanently eliminated the environmental noise problem which allowed the "planning blight" to be lifted. Consequently, planning consent was granted for 200 properties to be built on a site previously considered too noisy for housing (making it now worth £millions) at a cost to the developers of less than £45k.

  • vibration control
  • nuisance
  • noise control
  • environmental noise

Tunnel Boring – low frequency noise and vibration control

tunnel boring vibratory sieve noise reduction

Local residents were complaining about low frequency noise and vibration from a large tunnel operation which also exceeded the overall planning consent noise levels. The low frequency noise and vibration was generated by the spoil processing vibratory sieves and the previously proposed remedial measures included a deep ditch and a very large barrier. Neither of these would have been effective...

Our detailed diagnosis showed that the main problem was caused by excitation of some of the steel building wall and roof panels that then radiated the vibration very efficiently as noise. The panels we had identified as a problem were de-tuned quickly and cheaply by introducing stiffening ribs. This reduced the 15Hz noise radiation by 8dB which was sufficient to prevent further complaints.

We have also generated a comprehensive technical note on all aspects of vibratory feeder, hopper, conveyor and grader noise...

  • power press
  • nuisance
  • noise control
  • environmental noise

Power Press Shop – impulsive noise problems

power press noise reduction

Complaints about press noise from a factory unit had resulted in an Abatement Notice from the Local Authority. After the company had spent over £12000 on the building to no avail and with another £65000 expenditure planned as recommended by noise consultants (but without any guarantee that it would solve the problem), they had decided to challenge the notice in court.

However, as our Best Practicable Means (BPM) Noise Control Audit for the Local Authority proved that the best solution was to treat the small number of power presses that were causing the issue at source at a fraction of the cost of legal fees, this approach was adopted by the company. The engineering source control measures reduced the low frequency noise components by 9dB - 24dB, eliminating further complaints. This is a classic case where consultants have not carried out detailed diagnostic work to identify the precise causes of complaints, who do not have the engineering skills needed to design source control modifications and are therefore limited to recommending conventional palliatives that are not best practice at a very high cost to the client, the LA and to the disturbed residents.

  • nuisance
  • planning
  • noise control
  • environmental noise

Combined Heat and Power Station Planning and Noise Reduction

A new CHP installation on a large industrial site next to a housing estate was subject to very stringent planning constraints with respect to noise. A full impact assessment was made and, in conjunction with both the supplier and the Local Authority, a detailed noise specification drawn-up for all components of the installation.

We not only produced the noise specifications, but also provided detailed engineering noise control measures for the CHP installation project. An innovative approach was used to cut the expected cost of the overall noise control measures to meet the noise specification by approaching 90% by developing low cost engineering modifications to reduce the noise from other contributory sources on the site (fans, compressors, pumps, gas mains...) at the nearest dwellings by 8dB(A). This meant that the stringent noise attenuation requirements for the CHP installation could be significantly relaxed to generate very substantial cost savings.

  • nuisance
  • noise control
  • environmental noise
  • burner
  • combustion
  • boiler

Dual Fuel Burner Noise Reduction – yoghurt based control!

burner combustion head noise control

The cause of complaints about environmental noise levels was traced to this dual fuel burner boiler on a Heinz site. The company contacted us to assess the noise control options as the conventional palliative noise control techniques for this sort of problem involve fitting large silencers into the stack and converting the boiler house into an acoustic enclosure – eye-wateringly expensive with extensive downtime (which would have caused serious production problems).

The source was diagnosed as a 116Hz low frequency “drone” – a very common type of burner noise control problem – with a stunning simple alternative solution that comprised a set of aerodynamic modifications that fitted inside the combustion head. The initial trials were conducted using an adapted yoghurt pot fitted inside the burner head – as far as we know, this is the only known yoghurt-based noise control application… The modified pot reduced the drone by 16dB, completely eliminating the problem.

The cost? Less than £2k with a downtime of a few hours (aluminium version of the yoghurt pot). This new approach and technology can be an incredibly cost-effective solution to many burner or combustion noise problems.

Industrial boiler burner noise attenuation

There are usually only 2 noise sources on industrial boilers and burners:-

  • combustion fan: broadband and/or tonal noise at the fan blade pass frequency. Easily controlled using a simple silencer and/or aerodynamic fan noise control technology
  • combustion noise in the boiler burner: broadband sound - but very often with a pronounced low-frequency signature (and sometimes pure tones) that can travel large distances (a common cause of complaints). Traditionally, the suggestion is often to spend a large fortune to turn the boiler house into an effective acoustic enclosure. Our alternative is to address the problem at the source - as above...

  • nuisance
  • planning
  • noise control
  • environmental noise

Quarry Noise Attenuation - planning and execution

quarry planning noise management

A detailed environmental noise impact assessment established 24 hour target noise levels for a new quarry as part of the planning submission. This was supported by predictions of the changes in the local noise environment throughout the working life of the quarrying project and a detailed compliance verification procedure.

Detailed Buy Quiet noise purchasing specifications were provided for every piece of plant to be installed within the quarry. These included the measurement procedures and the best practice noise control measures that should be used by the suppliers to ensure that the target noise levels were met as cost effectively as possible (most suppliers have very little knowledge of noise control engineering technologies).

  • nuisance
  • noise control
  • impact noise
  • environmental noise
  • recycling

Scrap Recycling Impact Noise Control

scrap recycling yard impact noise control

£250 000 cost saving on environmental noise control…

Everyone knows that massive noise barriers are the only solution for noise from scrap yards and recycling centres. Everyone knows wrong...

We saved a scrap recycling company over £250 000 on the proposed noise barriers by controlling the dominant scrap impact noise at source. This is new technology that can reduce the impact noise from crushers in quarries, dump trucks, shredders, trains, manual handling etc by up to 15dB(A). Compared with conventional noise control techniques, the cost is miniscule, it is incredibly rugged, can be fitted very quickly and has no effect on plant operation, maintenance or access.

  • damping
  • noise control
  • petrochemical
  • environmental noise

Power Station Gas Facility – high damping noise reduction

Gas pipeline acoustic lagging noise control

Noise levels from a power station were uncomfortably close to their environmental noise planning conditions. Detailed diagnosis proved that the dominant contribution was high-frequency noise (>500Hz) radiated by the Gas Reception Facility. Vibration measurements narrowed-down the source to the reducer, expander and associated valve section of the facility.

Sound Damped Steel was brought in to fabricate our innovative, high-performance acoustic lagging. This has an outer skin constructed from highly damped laminated steel, making it very tolerant of installation practicalities. Moreover, options are available that eliminate the corrosion problems inherent in conventional lagging designs. The diagnostic process illustrates how costs can be kept to an absolute minimum by precisely ranking noise contributions from different components, even amidst complex arrays of pipework, valves and other sources. The effect of the treatment was to reduce the noise from this source by 16 -19dB(A), eliminating it as a contributor off-site. Occupational noise levels in the area were also reduced by an average of 8dB(A). More information is available on the Sound Damped Steel installer website here.

  • infrastructure
  • rail
  • noise control
  • environmental noise

Edgware Road Station – nighttime track maintenance noise

Edgware road station noise complaint reduction

From regular noise complaints to less than zero complaints…

As the station is overlooked by apartments, nighttime noise from underground track maintenance activities had given rise to regular complaints from local residents. The contractor, Balfour Beatty, decided to be proactive by asking us to introduce our new Acoustic Camouflage technology.

This solution involved relocating welfare facilities to take advantage of existing site screening features coupled with temporary acoustic barriers – not just for the facilities, but also for the vehicles and workforce at the station entrance. Then a pair of Acoustic Camouflage systems were installed at the station entrance and near the welfare area to dispense non-directional, shaped signature background noise. Despite raising the background noise by 8dB(A) at key locations, it was subjectively inaudible on the other side of the street. As a result, these systems were very successful at camouflaging the key annoying elements in the noise from the site activities.

The end result was not just to reduce the number of complaints to zero, but congratulatory emails were received from previous complainants complimenting the company on the effectiveness of their noise management...

  • buy quiet
  • fans

Plant Noise Information – the lack of frequency data from suppliers…

Fan tonal noise waterfall analysis

The most compromising and common issue we encounter is that plant noise data (fans in particular) never includes frequency signatures. Octave bands: yes. Narrow band (that defines if there is a tone): no. If there is a tone, in the UK it attracts a 6dB penalty – which only puts your predictions out by a factor of x4! Consequently, if you want to play safe, you over-engineer mitigation which adds a massive cost overhead. This is unacceptable. We try to get round this by asking for a smartphone recording from an installation anywhere in the world so we can design the optimum noise control measures.

This is a ridiculous state of affairs considering that you can do an accurate narrow band tonal analysis with a smartphone app for free. Noise consultants are also to blame as only a very small proportion of them carry out tonal analyses.

  • damping
  • pump
  • noise control

Power Station 600hp Water Pump Noise Reduction

Power station water pump noise control

These water pumps generated 95 – 99 dB(A) and were the subject of a dispute with the suppliers re the agreed noise levels. Various acoustic barriers and partial enclosures were being considered – at high cost and with considerable access issues. Our detailed vibration analysis proved that the required noise reduction could be achieved simply via constrained layer damping plus laminated close shields. These provided a 12dB(A) noise reduction with no effect on access, operation or maintenance – and at a tiny fraction of the previously proposed costs.

This is an example of the efficacy of accurate diagnosis coupled with good engineering and knowledge of materials. More information is available on the Sound Damped Steel installer website here.

Showing 31 to 45 out of 104